Electrocochleography and Cochlear Implantation: A Systematic Review.

OBJECTIVE: Given the heterogeneity of papers about electrocochleography (ECochG) and cochlear implantation (CI) and the absence of a systematic review in the current literature, the aim of this work was to analyze the uses of ECochG in the different stages of CI. DATA SOURCES: A search of PubMed from inception to December 8, 2019, with cross-references, was executed. Keywords were: "Cochlear Implant" OR "Cochlear Implantation" AND "Electrocochleography" OR "ECochG." The main eligibility criteria were English-language articles, investigating the use of ECochG in the different phases of CI. STUDY SELECTION: Literature reviews, editorials, case reports, conference papers were excluded, as were papers in which ECochG was just sporadically executed. DATA EXTRACTION: The quality of the included studies was assessed using "The Strengthening the Reporting of Observational Studies in Epidemiology" (STROBE) Statement. DATA SYNTHESIS: A total of 95 articles were identified and 60 papers were included. The included articles covered a timeframe from 2003 to 2019. Of the 60 papers, 46 were human studies, 12 animal studies, and two involved more data sets. Eleven related to the diagnostic phase, 43 described intraoperative monitoring, and 10 were regarding follow-up testing. Hearing preservation was the most discussed topic with 25 included articles. CONCLUSIONS AND RELEVANCE: ECochG measurements appeared to be useful in many aspects of CI, such as hearing preservation. Our review is the first that shows the evolution of the technique and how much has been achieved from the earliest experiments to the most recent signal process refinements and device implementation in CI.